bbb bbi bbk bbo bbr bbt bi- bib bii bik bio bir bit bkb bkk bko bkr bkt bob boi bok boo bor bot brb bri brk bro brr brt btb bti btk bto btr btt ibb ibi ibk ibo ibr ibt iib iii iio iir iit ikb iki ikk iko ikr ikt io- iob ioi ioo ior iot ir- irb iri irk iro irr irt itb iti itk ito itt k-t kbb kbi kbk kbo kbr kib kii kik kio kir kit kkb kki kkk kkr kkt kob koi kok koo kor kot kri krk kro krr krt ktb ktk kto ktr ktt o-i ob- obb obi obk obo obr obt oib oii oik oio oir oit okb oki okk oko okr oo- oob ooi ook ooo oor oot or- orb ori ork oro orr ort ot- otb oti otk oto otr ott rbb rbi rbk rbo rbr rbt rib rii rik rio rir rit rkb rkk rko rkt rob roi rok roo ror rot rrb rri rrk rrr rrt rtb rti rtk rto rtr rtt tbb tbi tbk tbo tbr tbt tib tii tik tio tir tit tkb tkk tko tkr tkt to- tob toi tok too tor tot trb tri trk tro trr trt ttb tti ttk tto ttr ttt